I assure you each IP address has only one reverse pointer at Digital Ocean. I know this because I set up the reverse pointer myself.
Original Message From: M.Roos@f1-outsourcing.eu Sent: October 26, 2020 4:41 AM To: lists@lazygranch.com; sami@ketola.io Cc: build+dovecot@de-korte.org; dovecot@dovecot.org Subject: RE: Looking for a guide to collect all e-mail from the ISP mail server
you should ask your ip provider to set a proper reverse lookup for you. If I would get a lot of spam from upcloud.host ips, I would also consider blocking upcloud.host reverse dns lookups. If it is your ip, it is an easy request to have it changed.
-----Original Message----- From: Sami Ketola [mailto:sami@ketola.io] Sent: Monday, October 26, 2020 11:22 AM To: lists Cc: Arjen de Korte; Dovecot Mailing List Subject: Re: Looking for a guide to collect all e-mail from the ISP mail server
On 26. Oct 2020, at 11.36, lists lists@lazygranch.com wrote:
Actually the reverse pointer doesn't have to match. In fact this is impossible if you are setting up virtual accounts on one server for different domains. You just need to have a reverse pointer.
Most email servers look to seen if the reverse pointer has a "dyn" in it and blocks those.
Also your own email server is not behaving nicely:
lists@lazygranch.com: host lazygranch.com[198.199.119.111] said: 500 5.7.1 <83-136-254-93.uk-lon1.upcloud.host[83.136.254.93]>: Client host rejected: eat a bag of dicks (in reply to RCPT TO command)
and for that reason I have blacklisted you from any help requests. You may do the same whatever you are telling me to do.
Sami